What is harder? What do you feel is more fun? Have you tried both or one or the other? How would you compare them? How would you compare poker machines, poker video games, and real poker to each other?
I have experienced both worlds. The real poker definitely has the challenge and the fun. It gives the opportunity to socialise with fellow players and that can help to sharpen your skills.
Honestly, I've never tried real poker. I've only played video poker. I was exposed to it a lot on the island of Saipan. They had video poker rooms everywhere.
Video poker can be convenient and fun. However, real poker has an unparalleled experience that cannot be replicated. The social aspect of that and the thrill of reading opponents are the real thing in poker.